Process of sulphonating beta naphthol



Patented Jan. 19.1926.

' UNITED STATES PATENT OFFICE."

moans L. caossrarsr, or soumwnmn, AND GEORGE s. smrson, or rtAmrIELD,NEW mnsny,

PROCESS OF SULPHONATING BETA NAPHTHOL' No Drawing.

To all whom it may concern:

Be it known that we, Mosns L. Cnossnar and GEORGE S. SIMrsoN, citizensof the United States, residing at Somerville and Plainfield,respectively, counties of Somerset and Union, respectively, and State ofNew Jersey, have invented certain new and useful Improvements inProcesses of Sulphonating Beta Naphthol, fully described and representedin the following specification.

This invention relates to improvements in the process of sulphonatingbeta-naphthol The object of the invention is to increase the yield,without increasing the cost of production. Of course, an increase of theyield of sulphonated beta-naphthol means there is less by-product, andit is a great advantage of the new process that there is less SO formed.4

The invention comprises the use of a special catalyst during thesulphonation process. We have found that certain com pounds of boron,articularly those containing oxy en, suc as boric acid or salts of boricaci act as very eflicient catalysts when present during the reactionbetween beta-naphthol and sulphuric acid. Such a catalyst improves theyield and the guality of the mixed sulphonic acids obtaine from thereaction. Only small amounts of th catalyst are required.

The amount of the catalyst may vary within considerable limits. It is animportant advanta of the invention that only a very sma amount isnecessary, as will ap car from the examples hereinafter set forth. Y

The catalytic material ma' be either boric acid or a salt of boric acias, for example, sodium borate. The ordinary technical or commercialgradesof these materials will be satisfactory.

In order to explain the invention further, we give two examplesillustrative of the invention, the proportions being given by weight. 1v

' Emample 1.

To 1000 parts of 100% sulphuric acid is added one part of boric acid orthe equivalent amount of some salt of boric acid. To

this mixture is then added 200 parts of beta-- Application filed October14, 1822. Serial No. 594,807.

naphthol while thoroughly stirring the mixture. The stirring iscontinued throughout the sulphonation.

After the addition of all thebeta-naphthol to the acid, the mixture isheated to raise the temperature gradually, for example, to 100 C. inabout two hours. Then it is held at about this temperature for about twohours, whereupon the sulphonation will be complete. The resultingmixture will consist principally of a mixture of sulphonic acids withsome sul huric acid.

The mixed sulphonic acids are reed of the excess sulphuric acid in theusual way. Then the mixture ofsulphonic acids may be treated in anysuitable way to separate them. i

E sample 2.

To 800 parts of sul huric acid of .a strength determined by t e kindsand rela-' tive amounts of beta-naphthol sulphonic acids to be producedthere is added a small amount of boric acid or a salt thereof. In

usual practice the amount of boric acid added either as acid or as acomponent of the salt may vary, but about 1 part is sufficie'nt for thequantity of sul huric acid stated above. Then 200 parts 0 beta-naphtholare added to the sulphuric.acid,this addition being made at a relativelyrapid rate, as, for example, in about two minutes. The mixture isthoroughly ,stirred during the addition of the beta naphthol and thestirring continued throughout the sulphonation.

The mixture is radually suitable source of heat so as to reach atemperature of about 100. C. in about two hours. It is then held at thattemperature for about three hours and then about 200 parts of 104%sulphuric acid are added within a definite period of time, usually aboutone hour. The temperature is regulated during theaddition of the oleumso as not to exceed the maximum required forv heated by a I may varyaccording to the products and the proportions thereof which it isdesired to obtain.

For example, if the sulphonated products are to contain nomono-sulphonic acids, the sulphonation is continued until a test samplefails to give the characteristic Schaefier 7 3. The process ofsulphonating belanaphthol, which comprises reacting upon it withsulphuric acid in the presence of a catalyst containing boric acid.

4. The process of sulphonating beta-naphthol, which comprises preparinga mixture of sulphuric acid and a catalyst comprising boric acid, thenadding the beta-naphthol while continuously stirring the mixture.

5. A. process of sulphonating beta-naphthol which comprises preparing amixture of sulphuric acid and a heron compound containing oxygen, thenadding beta-naphthol while stirring the mixture, then gradually raisingthe temperature of the mixture to about 100 0., and maintaining it atthis temperature for several hours until the sulphonation is complete.

In testimony whereof, we have hereunto set our hands.

MOSES L. GROSSLEY. GEORGE E. SIMPSON.

